1. Field of the Invention
The present invention relates generally to the construction and use of vascular catheters. More particularly, the invention is a catheter including a strainer device which is used for the intraarterial retrieval of emboli, normally while performing angioplastic procedures.
A variety of non-surgical angioplastic procedures have been developed for removing obstructions from blood vessels. Balloon angioplasty utilizes a balloon-tipped catheter which may be inserted within a stenosed region of the blood vessel. By inflating the balloon, the stenosed region is dilated. Laser angioplasty utilizes laser radiation for ablating a stenosed region. In theory, the plaque or thrombus is vaporized and dissolved in the bloodstream where it is eliminated by normal bodily functions. Other techniques, such as atherectomy and suction angioplasty have also been proposed. In atherectomy, a turning blade is used to shave plaque from an arterial wall while in suction angioplasty a vacuum is used to draw plaque or thrombus out of the blood vessel through a suitable catheter.
One problem common with all of these techniques is the accidental release of portions of the plaque or thrombus, resulting in emboli which can lodge elsewhere in the vascular system. Such emboli are, of course, extremely dangerous to the patient, frequently causing severe impairment of the circulatory system. Indeed, in the worst cases, multiple emboli are released which can so severely reduce peripheral blood circulation that amputation becomes necessary.
For these reasons, it would be highly desirable to provide an apparatus and method for preventing embolisms associated with conventional angioplastic procedures. In particular, it would be desirable to provide a device which could be located within the vascular system to collect and retrieve portions of clot and thrombus which are dislodged during the angioplastic procedure.
2. Description of the Background Art
U.S. Pat. No. 3,952,747 describes a stainless steel filtering device which is permanently implanted transvenously within the inferior vena cava. The filtering device is intended to treat recurrent pulmonary embolism. A device constructed pursuant to the teachings of the patent is sold by Medi-tech, Inc., Watertown, Massachusetts, as described in their Bulletin VCF-1.